Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014		Sep. 30, 2013
Homebuilding [Member]
Fair value balance sheet items measured on a recurring basis
Other Investments	$ 20.8		$ 20.3
Homebuilding [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Fair value balance sheet items measured on a recurring basis
Other Investments	0	[1]	0	[1]
Homebuilding [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Fair value balance sheet items measured on a recurring basis
Other Investments	0	[1]	0	[1]
Homebuilding [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Fair value balance sheet items measured on a recurring basis
Other Investments	20.8	[1]	20.3	[1]
Homebuilding [Member] | Estimated Fair Value [Member] | Fair Value, Measurements, Recurring [Member]
Fair value balance sheet items measured on a recurring basis
Other Investments	20.8	[1]	20.3	[1]
Financial Services [Member]
Fair value balance sheet items measured on a recurring basis
Mortgage loans held for sale	419.2		395.1
Financial Services [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Fair value balance sheet items measured on a recurring basis
Mortgage loans held for sale	0	[2]	0	[2]
Financial Services [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Interest rate lock commitments [Member]
Fair value balance sheet items measured on a recurring basis
Fair value of interest rate derivatives	0	[3]	0	[3]
Financial Services [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Forward sales of MBS [Member]
Fair value balance sheet items measured on a recurring basis
Fair value of interest rate derivatives	0	[3]	0	[3]
Financial Services [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Best-efforts and mandatory commitments [Member]
Fair value balance sheet items measured on a recurring basis
Fair value of interest rate derivatives	0	[3]	0	[3]
Financial Services [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Fair value balance sheet items measured on a recurring basis
Mortgage loans held for sale	409.9	[2]	389.4	[2]
Financial Services [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Interest rate lock commitments [Member]
Fair value balance sheet items measured on a recurring basis
Fair value of interest rate derivatives	3.5	[3]	7.0	[3]
Financial Services [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Forward sales of MBS [Member]
Fair value balance sheet items measured on a recurring basis
Fair value of interest rate derivatives	(4.6)	[3]	(8.8)	[3]
Financial Services [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Best-efforts and mandatory commitments [Member]
Fair value balance sheet items measured on a recurring basis
Fair value of interest rate derivatives	(0.8)	[3]	(3.1)	[3]
Financial Services [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Fair value balance sheet items measured on a recurring basis
Mortgage loans held for sale	9.3	[2]	5.7	[2]
Financial Services [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Interest rate lock commitments [Member]
Fair value balance sheet items measured on a recurring basis
Fair value of interest rate derivatives	0	[3]	0	[3]
Financial Services [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Forward sales of MBS [Member]
Fair value balance sheet items measured on a recurring basis
Fair value of interest rate derivatives	0	[3]	0	[3]
Financial Services [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Best-efforts and mandatory commitments [Member]
Fair value balance sheet items measured on a recurring basis
Fair value of interest rate derivatives	0	[3]	0	[3]
Financial Services [Member] | Estimated Fair Value [Member] | Fair Value, Measurements, Recurring [Member]
Fair value balance sheet items measured on a recurring basis
Mortgage loans held for sale	419.2	[2]	395.1	[2]
Financial Services [Member] | Estimated Fair Value [Member] | Fair Value, Measurements, Recurring [Member] | Interest rate lock commitments [Member]
Fair value balance sheet items measured on a recurring basis
Fair value of interest rate derivatives	3.5	[3]	7.0	[3]
Financial Services [Member] | Estimated Fair Value [Member] | Fair Value, Measurements, Recurring [Member] | Forward sales of MBS [Member]
Fair value balance sheet items measured on a recurring basis
Fair value of interest rate derivatives	(4.6)	[3]	(8.8)	[3]
Financial Services [Member] | Estimated Fair Value [Member] | Fair Value, Measurements, Recurring [Member] | Best-efforts and mandatory commitments [Member]
Fair value balance sheet items measured on a recurring basis
Fair value of interest rate derivatives	$ (0.8)	[3]	$ (3.1)	[3]

[1] In October 2012, the Company purchased defaulted debt securities which are secured by residential real estate. These securities, which are included in other assets in the consolidated balance sheets, are classified as available for sale and are reflected at fair value. At June 30, 2014, the fair value of these securities was based on a recent agreement with an outside third party to sell the securities. Unrealized gains or losses on these securities, net of tax, are recorded in accumulated other comprehensive income (loss) in the consolidated balance sheets.

[2] Mortgage loans held for sale are reflected at fair value. Interest income earned on mortgage loans held for sale is based on contractual interest rates and included in financial services interest and other income. Mortgage loans held for sale at June 30, 2014 includes $9.3 million of originated loans for which the Company elected the fair value option upon origination and which the Company has not sold into the secondary market, but plans to sell as market conditions permit. The fair value of these mortgage loans held for sale is generally calculated considering the secondary market and adjusted for the value of the underlying collateral, including interest rate risk, liquidity risk and prepayment risk.

[3] Fair value measurements of these derivatives represent changes in fair value and are reflected in the balance sheet. Changes in these fair values during the periods presented are included in financial services revenues in the consolidated statements of operations.